The present invention relates to an NC (Numerical Control) system, and more particularly to standby control in such a numerical control system for a multi-axis tool base, for instance, as employed for four-axis lathe machining.
For standby control in an NC of the type described it has been required to specify a standby code (an M code) in a machining program. It is difficult to know the standby timing for the tool base at the time of preparing the program. It has therefore been necessary to run the machining program once to extract positions which require standby operation of the tool base. Each time such a position is extracted, the machining program has had to be edited again to insert a standby code (an M code). Where standby codes (M codes) are inserted appropriately in the machining program upon preparation thereof, the time required for the machining operation contains unnecessary intervals. Re-editing the machining program for standby operation of the tool base has required a skilled operator and has resulted in a large expenditure of time.